<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>条件判断</title>
</head>
<body>
	<script>
		var score = parseInt(window.prompt('input'));
		if(score >= 60 && score <=70){
			console.log("及格");
		}
		else if(score >= 70 && score <=80){
			console.log("中等");
		}
		else if(score >= 80 && score <=90){
			console.log("良好");
		}
		else if(score >= 90 && score <=100){
			console.log("优秀");
		}
		else{
			console.log("不及格");
		}
	</script>
</body>
</html>